Date: Mon, 25 Oct 2010 20:31:49 +1100 From: Peter Jeremy <peterjeremy@acm.org> To: Jean-Francois Dockes <jf@dockes.org> Cc: freebsd-hackers@freebsd.org Subject: Re: dump cache performance Message-ID: <20101025093149.GA67314@server.vk2pj.dyndns.org> In-Reply-To: <19652.22833.731361.647776@y.dockes.com> References: <AANLkTikzZvZn=vNNRtcSViWq8ty7b8qOooQ4NbHiJH5q@mail.gmail.com> <4CC44E5B.9040902@infracaninophile.co.uk> <20101024152835.GA62748@muon.cran.org.uk> <19652.22833.731361.647776@y.dockes.com>
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On 2010-Oct-24 18:05:05 +0200, Jean-Francois Dockes <jf@dockes.org> wrote:
>It appears that modifying dump to use a shared cache in a very simple way
>(move the control structures to the shared segment and perform simple lock=
ing)
>yields substantial speed increases.
Indeed. That's better than I expected.
>Would someone be interested in reviewing the patch and/or perform
>more tests ?
I've mostly convered to ZFS but still have UFS root (which is basically
a full base install without /var but including /usr/src - 94k inodes
and 1.7GB). I've run both the 8-stable ("stable") and patched ("jfd") dump=
=20
alternately 4 times with 50/250MB cache with the following results:
x stable
+ jfd
+------------------------------------------------------------+
| +|
| +|
| x +|
|x xx +|
||AM A|
+------------------------------------------------------------+
N Min Max Median Avg Stddev
x 4 9413 9673 9568 9555.5 107.12143
+ 4 15359 15359 15359 15359 0
Difference at 95.0% confidence
5803.5 +/- 131.063
60.7347% +/- 1.3716%
(Student's t, pooled s =3D 75.7463)
--=20
Peter Jeremy
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